Poor customer service

Hi

I was contacted my FNB to settle my overdraft with a 25 percent discount on the 28th of October, I made payment the same day, it has been more than a month and I haven't received the discount yet, interest and bank fees are being charged on my account. I have been back and forth to FNB, spending hours on the phone wasting my airtime and time, they keep pushing me from department to department yet I have done my part. Ot is so simple to write the balance off as per agreement